Main and auxiliary control valve arrangement for grounded aviation trainers



2 6 4 1 2 T N m E N am L Awm HUN Lm mm ET I Ywm A D Y E mm July 11, 1950 5.

MAIN AND AUXILI FOR GROU Filed Jan. 2, 1948 6 Sheets-Sheet l STANLEY I. HAYES THEODORE H KOVITZ VENTORS BY W1 b 0 3 N m m m m M m R N WR O M T M E L FIG.

ATTORNEY s. l. HAYES ETAL 2,514,762 MAIN AND AUXILIARY CONTROL VALVE ARRANGEMENT FOR GROUNDED AVIATION TRAINERS Filed Jan. 2, 1948 6 Sheets-Sheet 2 July 11, 1950 FIG. 2

STANLEY l.' HAYES THEODORE HERSKOVITZ IN V EN TORS Isl WA ATTORNEY y 1950 s. I. HAYES ETAL 2,514,762

MAIN AND AUXILIARY CONTROL VALVE ARRANGEMENT FOR GROUNDED AVIATION TRAINERS Filed Jan. 2, 1948 6 Sheets-Sheet 3 308M512 Y 308 v FIG. 3'

STANLEY I. HAYES THEODORE HERSKOVITZ INVENTORS ATTORNEY I. HAYES El AL ARY CONTROL VALVE ARRANGEMENT July 11, 1950 s. MAIN AND AUXILI FOR GROUNDED AVIATION TRAINERS 6 Sheets-Sheet 4 Filed Jan. 2, 1948 nm Y wm v E O N mwKm R s 0 m T mHW. M vm X E w ms mow mm 00% W mm? vwv mwv Iv 0 .523 4 O v Oummm NwV E4 ORV Ono wmm July 11, 1950 s. l. HAYES ET AL 2,514,762

MAIN AND AUXILIARY CONTROL VALVE ARRANGEMENT FOR GROUNDED AVIATION TRAINERS Filed Jan. 2, 1948 6 Sheets-Sheet 5 STANLEY HAYES 8 THEODORE HERSKOVITS IN V EN TORS.

ATTORNEY July 11, 1950 s. l. HAYES ET AL 2,514,762 MAIN AND AUXILIARY CONTROL VALVE ARRANGEMENT 7 FOR GROUNDED AVIATION TRAINERS Filed Jan. 2, 1948 6 Sheets-Sheet 6 FIG.

FIG. II

STANLEY l. HAYES THEODORE HERSKOVITS INVENTORS. W4M' ATTORNEY Patented July 11, 1950 MAIN AND AUXILIARY, CoNTROLVALVE ARRANGEMENT FOR 'oRo ND VIA- TION TRAINERS Stanley I. Hayes and Theodore Herskovits, Binghamton, N. Y., .asslgnors toLink Aviation, Inc., Binghamton, N. Y., a corporation of.New York Application January 2, 1948, Serial N o. 328

. l 1 This invention relates to a main valve construction and auxiliary trim valve construction for use in conjunction with grounded aviation trainers of the type employing a fuselage. universally and rotatably mounted with respect to a stationary base together with pneumatically operated means for producing pitching, banking and turning movements of the fuselage to simulate the turning, pitching and'banking of a plane in actual flight. such trainers are-disclosed in United States Patents 1,825,462 and 2,099,857 issued to Edwin A. Link. l The copending application of Samuel Arthur Douglas, Serial Number 631,906, filed November 30, 1945, forValve Construction for Grounded Aviation Trainers, which since the filing of this application has matured into Patent 2,469,918, dated May 10, 1949, discloses a maincontrol valve for use in conjunction with trainers of the type just mentioned, the control valve comprising a series of five different valve sections all mounted upon the same vertical axis together with means forrotatin certain of the sections in response to movements of the controlstick and rudder pedals in the fuselage, and in response to bank'- ing movements of i the fuselage in order to control the bellows and turning motor to cause the fuselage to turn, pitch and bank according to movements of the manually operable controls and'of the fuselage.

The apparatus disclosed in this invention is in part animprovement upon the type of valvearrangement disclosed in Patent 2,469,918.

Thevalve arrangement disclosed in this ap'-' plication comprises eight sections including a lower fixed leaf, a leaf immediately thereabove for accomplishing the automatic turn withbank effect, and a rudder leaf positioned above the second mentioned leaf. The rudder leaf is connected to the rudder pedals in the trainer to be rotated in response to movements thereof, and theports in the rudder leaf are arranged to bepositioned relative to the ports in the second mentioned leaf and the ports in the second-mentioned leaf are arranged tobe positioned relative to thelowermost fixed leaf so that the operation of the turning motor is responsive to the relative rotational positions of the second mentioned leaf and the rudder leaf to produce turning of the fuselage according to the combined positions of the rudder pedals and banking position of the fuselage. Above the rudder leaf is positioned a station ary leaf and above the stationary. leaf is posi- ,t lo'ned a leaf which is operated by" banking ac- 6 Claims. (alias- 12) tion of the fuselage.

2 Above the last mentioned leaf is positioneda fixed leaf which has ports connecting to themain four bellows which control thepitching and banking movements of the fuselage. Ports are placed in the upper surfaceof the rudder leaf and in the other leaves between the rudder leaf and the leaf having connections to the bellows so that upon a rotation ofthe rudder :leaf in response to rudder pedal action a. banking of the fuselage automatically results. The ports in the leaf immediately below the fixed. leaf having lines extending to the four bellows are arranged so that upon a rotation of the, leaf inresponse to a banking of the fuselage'the attitudebellows are selectively operatedto produce a nosing down of the fuselage in response to a banking thereof.

:Abovemthe fixed leaf having the pneumatic lines.-.running,to the four bellows is provided a stall leaf which is pivotally mounted with respect to the just mentioned fixed leaf, and above the stall leaf is provided a vacuum cap which moves around with respect to the ports in the stall leaf toselectively apply vacuum to the ports in thestall leaf and: to the ports in the fixed leaf immediately thereunder according to the position of the control stick which is connected to .the vacuum cap to position the same. Consequently, movements of the control stick selectively apply vacuum and atmosphere to the pneumatic'line running from the fixed leaf to the four. main bellows to control the pitching and banking movementsof the fuselage. The stall leaf in turn is connected to an actuating unit which is controlled by the air speed unit in the trainer'so that when air speed drops to a predetermined amount, corresponding to the stallv ing iairspeedof the plane being simulated, the

stall leaf is rotated upon the mentioned pivot to applyvacuurn to the ports in the fixed leaf immediatelytherebelow connected to the front pitching bellows and to ventthe ports in the same l-eafccon'nectedto the rear pitching bellows to the atmosphere, .to produce a sudden nosing down'of the fuselage to simulate the stalling of a plane in actual flight.

Also, the fixed leaf having the pneumatic lines extending to the four main bellows has a pair of ports and pneumatic lines connected thereto which. extend to the turning motor. The stall leaf" has a-pair of ports arranged above the two mentioned'ports'in the fixed leaf immediately therebelow so that upon movement of the vacuum cap in response to sidewise movements of the" control stick vacuum and atmosphere are selectively admitted to the turning motor to turn the fuselage slightly in the opposite direction from which the fuselage is banked, thus simulating the aileron drag or adverse yaw efiect experienced in actual flight.

An auxiliary, valve is also provided by this invention, this trim valve having ports connected to the four main bellows, the various leaves of the trim valve being operated by the simulated throttle control lever and simulated elevator qontrolleyer.

in the trainer, as well as by thepitch actiontakaoff mechanism, to control the pitch attitude of the fuselage in response to thecombined settings of the throttle lever and trim lever; and; pitch; attitude of the fuselage. Thctrim, valve is. supplied by vacuum from the previously described main valve and the supply of vacuumis-respomsive to the position of the movable leaf positioned,

above the lowermost fixed leaf of the main valve which in turn is responsive to the banking position of the fuselage to reduce theeffect of throttle lever position, trim leverpositiori and pitch attitude upon the pitch attitude of: the fuselage asbanking of thefuselageincreases.

In order that the preferred embodiment of our invention may be clearly understood, reference is made to the accompanying drawings, wherein-1 Fig. 1 is a side view of a trainer withwhichourinvention maybe employed, showing theigeneral arrangement of the parts of this invention.

Fig. 2 is an exploded perspectiveyiew of the four bottom leaves of the main: control valve. of this application.

Fig. 3 is an exploded perspective view of the three. top leaves of the main valve: of thisapplie cation, and of the vacuum cap and associated parts.

Fig. 4 is a 'bottom view of the lowermosts-tationary leaf of the mainvalve of thiszapplication, showing some of the fittingsattachedthereto.and the pneumatic lines connected tothe turning motors and trim valve.

Fig. 5 is a partial cross-sectional view of'the lowermost fixed leaf of the main valve.

Fig. 6 isa perspective-view. showing. the general relative positions and connections between the main parts of theapparatus of this-invention.

Fig. '7 is a perspective view ofa portion ofthe rudder-leaf of the mainvalve.

Fig. 8 is a top view of the main valve;leaf.which is connected to the four main bellowsland'; turning motors, and also showing the connections, bellows and motors.

Fig. 9 is an exploded detailed-view oft=the leazves of the trim valve of thisv application.

Fig. 10 is aview showing theoonnectionsfrom the trim valve to the four main bellows, and" Fig.- 11 is a cross-sectional view of; the trim valve.

Reference is made to Fig. 1-:wher'e-the fuselag I0 of the trainer is shown, in which: isplaced" a seat l2 for the studentusing the trainer. The bottom of the fuselage isdesignated lllaandrests upon the universaljoint' designated; generally by M which is supported by the.vertical spind1 -.l5 held by the bearing housing. H" which in turr'i; is held by the stationary: base It. The left-gfront bellows 26, the right front bellows 22,- theleftyrear bellows 26 and the right rear -bellows:26 areshown, each of th sebellowshaving its lower-end affixed to the framework 28;whichis a'ffiXBd'ftO the; vertical spindle l6'*to rotate there-with; butinasrnuch as the framework 28is affixed tothespindle below the: universal joint 14,. itzwill be. appreciated that the framework doesnottilt: The, ;turning -.motors ergization of the turning motor in response to the operation of the apparatus hereinafter disclosed, The pump for the supplying of vacuum is designated 3-9, and is driven by motor 390., the pump,- and, motorbeing affixed to framework 28 by arms 3%.

Placed ahead of the seat l2 in the trainer is the-stick 4,0 whichsimulates the control stick of a real'plane, and ahead of the control stick are thezleft;and-ri htzrudder pedals 42 and M.

Itwillbe noted that unlike the prior art trainers, none of the four main bellows 20, 22, 24 or 26 is on the longitudinal or transverse axis of the fuselage H], butthat bellows 2i] and122eareahead of the transverse axis and bel'lows wand; 2'62are to therear of the transverse axis, while bellows 20- and 2&- are to the leftof the-longitudinalr axis and bellows: ZZ'and Zfia-rc totheright of theilongitudinal' axis. The-upper end of'each of'the four bellows is connected to. the bottom. lllawofi the fuselage;

Reference-is now made to Fig.2where the=.lower, sections of'the improved main valve of this application which isdesignated" generally. by 5.0 dis:- closed. f

Considering now the detailed, construction; of the-lowermost fi-Xedleaf 52 of valve 50, this-leaf has a pair of threaded taps (not shown) in its bottom for the reception of apair-of-zscrews': (not shown) which pass: upwardly: throughsthexbase plate 5 la which is afflxedito the -bottom ififa.ofrthe fuselage by bolts: 511), as seen in Fig; 6,. towhold' leaf 52=stationary relative to the: base platenv I'Seaf 52 hasa pairof verticalportsfidand. 5.61; which extend completely through this leafyandasseen in Fig.- 4, a fitting 58 is insertediin the: lower: end of'port 5 k and is: connectedbythe pneumaticsline 6!! which runs to the left turningmoton 3.0a, while a fitting 64'is: inserted in thelower end ofeportcfli and isconnected by means of" pneumatic: line-65 with the-right turning motor-361),. Referringback to Fig. 2, positioned counterclockwise ofi-thezpoiz 54 is a port Ill which opens through; the upper face of leaf 52 and isconnected; through the interior channel 12 with. the .portit. which opens through the lower face of lea-fl 52.: Positioned clockwise of thepport 56 is;v port; 16-. which, also opens throughthe'upper face, ofleaf, 52, and: is connected. through; the interior channell8-with port 14;, As seen'in Fig; the fitting 801is inserted, in the; port M and is; connected, through the pneumatic-line 8 2;wit h the -tr-i-m va1ve=desig nated gen rally. bvi

In Fig.,21it will be seen that the vertical central opening 86;-of leaf 52 passescompletely through the leaf; and as seen inFig; 5, there, is inserted therein;tigh t fitting relationtheicentral stem. 88,.which is connected by means of pneumatic; line 90- to the pump-.39 which -providesa-su-itable sourceof reduced-1 pressure or; vacuum. The-central. stem 88;: has any Opening: 91 l;..-w hich overlies the, opening ofwportrQBi into the; central bore- 86 of leaf 5.2. Port 98;r unshorizontallywithinz-leaf 5-2 part way touthe peripheryrthereof; and then extends vertically and. opens throughthe upper, faceofileaf 52.1, Accordingly the port ears at alltimessupplied with reduced pressure or-vacuum.

111.31% 2 the turn- .withbank leaf which lies ,on

. 5- thebase leaf 52 isinumbered' I andhasj a central opening I02 into which fits the central stem wand about iwhich theleaf I00 rotates-in response, tobanking action of the fuselage I0, as will be explained. Leaf I00 has a third pair of ports I04, and I00 I which extend completely y through ,this' leaf, port I04 being arranged to I A third pair-of ports '2 and H4 pass completely thrqughtheleaf I00, these two ports being arranged to lie upon opposite sides of the port 08 in leaf 52 when leaf I00is centered, with no overlap between the ports. The leaf I00has'an integral arm'-I I6 having two holes I I1 therein, arm H0 also being shown in Fig. 6 to which reference is now made.

In Fig. 6, the bottom I0a of the fuselage I0 isshown and afiixed'to the bottom by bolts 400 is the'universal joint base plate 402 integral with which is the upright square-shaped casting 404 whichis the outer member of the universal joint I4. l-The inner gimbal of the universal joint is numbered 400 and is rotatably mounted about the transverse axis 40101. by means of the rod 401. which passes through the upper end of the vertical spindle I0. Gimbal 406'has two integral bearing housings. 408 containing bearings (not 1 shown) held by the outer ends of the transverse r'od40l' top'ermit pivoting of gimbal 400 about y axis 401a. A first longitudinally extending shaft 409 has: its rear end rotatably mounted in the upright 404 while its forward end is pinned to the inner gimbal 400 by means of pin M0. The shaft 420 which has its longitudinal axis aligned with the longitudinal axis of rod 409 is rotatably held by the upright 404 and the bearing housing 4I I carriedthereby, the rear end of rod 420 being pinned to the inner gimbal 400 by means of pin 4|2. I

a By virtue of this arrangement, it will be appreciated that when the fuselage I0 is pitched about the'transverse axis 401a in response to an operation of the four bellows 20, 22, 24 and 20, the fuselage I0, bottom I 0a, outer. member 404 and inner 'gimbal 400 rotate about the transverse axis 401a. When fuselage I0 is banked in response to an operation of the same bellows, the fuselage I0, bottom Ma and outer universal joint member 404 rotate about the longitudinal axis 4I3which is the axis of rods 420 and 409. It will be noted that the rod 420 does not rotate about axis M3 in response to a banking of fuselage I0.

, Affixed upon the forward end of the fixed rod 4'20 by screws 422 is the bifurcated arm 424 integral with which is the stud 420 the outer end of which lies between the bifurcated lower end of arm 428, the upper end of which is afixed to the outer end of arm II5 integral with leaf I00 by bolts 430. When fuselage I0 banks to the left, the fixed rod 420 does not rotate and arm 424 remains vertically disposed, but the main valve and section I00 move to the right of the axis M3, and by means of stud 426 and arm II6 the leaf I00 is rotated clockwise as seen from above through an angle proportional to the angle of bank, When fuselage l0 banks to the right, leaf I00 isrotated counterclockwise through .an angle proportional to the angleof bank.

Considering now the detailed construction of the rudder leaf I20, a fragmentary perspective view of which is also shown in Fig. '7, to which figure reference is made in conjunction with Fig. 2, it willbe seen that this leaf has a central opening I22 completely therethrough for the reception of the central stem 88 and that the pe riphery of central stem 88 intermediate the upper and lower faces of leaf I 20 has a pluralityof holes I 24 which lead into the circular chamber I26 formed inside leaf I20 in order to supply the chamber I26 with vacuum at all times. A radially extending slot I20'is placed in the top of leaf I 20, the inner end of this slot being-connected with the chamber I20 and the outer end being connected with the arcuate slot I30 placed in the upper surface of leaf I20,. A vertical port I32 of restricted capacity opens into the center.

of the arcuate slot I30 in the upper face of the leaf I20 and also opens into the figure-of-eight port I34 in thelower face of the rudder leaf I20. By virtue of this arrangement it will be appreciated that the arcuate slot I30 is supplied with vacuum at all times, and by means of-port I32 the figure-of-eight port I34 in the bottom of leaf I I20 is atall times supplied with vacuum, but the rate of exhaustion of port I34 is restricted by the size of port I32. The figure-of-eight port edge of port I34 is offset from the clockwise end,

of port I08 a few thousandths ofan inch when leaves'lfil and I00 are neutrally positioned, and

the clockwise edge of port I34 is similarly dis placed from the counter-clockwise edge ofport,

IIO under the same circumstances.

The arcuate slot I30 is placed in thebottom,

of leaf I20 to overlie the port I04 in leaf I00 at all times, and slot I30 is connected by means of the interior channel I38 with the chamber I20 in the center of leaf I20.- A second arcuate slot I40 is also placed in the bottom of leaf I20 to overlie port I00 of leaf I00 at all times, slot I40 being connected by means of interior channel I42 with the vacuum chamber I20. Consequently, slots I30 and I40 aresupplied with vacuum at all times. The vertical port I44 opens through the upper face of the rudder leaf I20 and extends through to the vacuum filled slot I30 1n the bottom of leaf I20, while the vertical port I40 also opens through the upper face of leaf I20 and extends through to the vacuum filled slot I40 in the bottom of leaf I20. Afirst radially extending slot I48 which opens through the periphery of leaf I 20 is placed in thebottom of leaf I20 and is connected with the vertical port I50 which opens through the upper face of leaf I20, and a second radially extending slot I52 is placed in the bottom of leaf I20 and extends through to the periphery thereof, and is in communication with the vertical port I54 which opens through the upper face of leaf I20. It will be appreciated that ports I50 and I54 are open to the atmos the two leaves are neutrally positioned, and slot I I52 ispositioned in leaf I20 so that its counterclockwise edge similarly overlaps the clockwise end'of port H0 in leaf I00 under the same;

portedby the vertical post -441- rotatably held by-a fixed bearing 442 attached to member 443 afiixed in fuselage I0. The arm 444 is afiixed up on post 4-41 to rotate therewith, and the forward end of the rudder link 446 is pivotally attached to arm'444 while the rear end of link- 446 is pivotallyattached' tothe-hracket'448 which is suitably fixedly attached to-the edge of the rudder leaf I28. A pair of centering springs 452 each has one of its ends attached to the rudder bar and its other end attached to one of the studs 454 carried by member 456 afiixed to the interior of fuselage I0.

It will be appreciated that a forwarddisplacement of left rudder pedal 42 from its neutral position rotates the rudder leaf I20 clockwise as seen from above from its neutral position through an angle dependent upon the magnitude of dis placement of pedal 42 from its neutral position, and that a forward displacement of the right hudder pedal 44 from its neutral position rotates the-leaf I20 counterclockwise of its neutral position through an angle dependent upon the mag-- nitudeof displacement ofpedal 44 from its neutral position.

The stationary leaf which overlies the rudder leaf I20 is numbered I60 and is provided with an integral ear I62 having a hole I66 through which passes the retaining pin I'IEI shown in Fig. 6. The lower end of this retaining pin fits into a suitable hole in casting 5Ia. Leaf I60 has the central opening I-6I through which the fixed stem 88 passes, and a first port I'I4 which passes completely therethrough, this port being positioned slightly counterclockwise of the vacuum port I44 in the rudder leaf I20 when the rudder leaf I20 is in its neutral position. A second port "6 also passes completely through leaf I60, this port being positioned slightly clockwise of the vacuum port I46 in the upper surface of the rudder leaf I20 when the rudder leaf is in its neutral position. The atmosphere slot H56 which is positioned in the upper surface of the rudder leaf I20 is positioned just counterclockwise of port I14 in lea-f I60 when leaf I20 is'neutrally positioned, while the atmosphere slot I58, also in the upper surface of leaf I20, is positioned just clockwise of port I16 in leaf. I60 when the rudder leaf I20'is neutrally positioned. A slot I18 which extends radially of leaf I60 and opens through the periphery thereof is placed in the upper face of leaf I60, while a second slot I88 which also extends radially of leaf I68 and opens through the periphery thereof is also placed in the upper face of this leaf. A pair of kidney-shaped ports I32 and I84. pass completely through leaf I60, port I82 being arranged to lie slightly clockwise of the atmosphere port I50 in the upper surface of the rudder leaf I20 and slightly counterclockwise of the counterclockwise end of vacuum slot I30 in leaf I20 when the rudder leaf is neutrally positioned, and port I 84" being positioned to lie slightly counterclockwise of the atmosphere port I54 in rudder leaf I20 and slightly clockwise of the clockwise end of vacuum slot 530 in leaf I20 when the rudder leaf is neutrally positioned. Finally, a pair of ports I86 and I88 pass completely through leaf I60 and are arranged to 8 overlie the arcuate vacuum slot: I30 in the upper surface ofytherud'der leaf I20 at all times.

Reference is now made to Fig. 3 where a detained disclosure of the other three leaves of themain control valve 50 are shown, the nose-downwith-bank leaf which overlies the fixed leaf I60- ofFig. 2 being numbered I90. This leaf has a central opening I92a' for the reception ofthe. central stem 88. The; leaf I90 contains four kidhey-shaped ports I92, I94, I96, and I98 which pass completelythrough the leaf, these four ports, respectively overlying the ports I14, I16, I821, and I84 in they leaf I60 therebelow throughout the entire range of travel of leaf I90. Leaf I90" also contains an additional through port .200 which lies between the two ports I86 and I88 in. the fixed leaf I60 when leaf I90 is in itsv neutral position. Leaf I90 has an integral car 202 having a.

pair of holes 203 therethrough, and referring; to Fig. 6 it will be seen that the arm 204 is con.- nected to ear 202 by bolts 450 which pass through the previously described holes 203 in leaf I90. The upper end of arm 204 is bifurcated and between the forks thereof lies the stud 4,52 carried by the upper end of arm 454' which isaffixed: upon the fixed rod 4.20 by screws 456. By virtue of: the just described.v interconnection between leaf I and the: fixed, rod, 420;. leaf I80; is rotated counterclockwise ofv its neutral position as. seen from above in response. to a banking of. fuselage- I0 to the left and clockwise of its neutral position in response to a banking of fuselage III to the right; the angular displacement of: leaf lfrom its neutral position being proportional to the de-, gree of bank of fuselage I0.

Positioned above the noseedown-withmank leaf I96 is the fixed leaf .210 having an integral ear 252 having a hole 2H4 for the. reception of the vertical retaining-pin. I18, as seen in Fig. 6. The four ports 2J6, H8, 220 and222. open through the upper face of the fixed leaf-2:I0;..and. each of these ports passes interiorly downward and then radially of leaf 210 to open through the periphery thereof. As shown in Fig; 8, the-fitting 22.4 is placed in port 216 and is. connected through the. pneumatic line 226 to the left rear bellows 24.; the fitting 22% is placed in the port M8 and is connected through pneumatic line-239totheright rear bellows 26'; the fitting 23.2 is placed in the port 220 and is connected through the pneumatic line 234 with the left front bellows 2.8; and the fitting is. placed in port 222 and is connected through the pneumatic line 238 with the right front bellows 22'. As seen in- Figs. 3 and .8, a pair of ports 240 and 2 32 open through the upper face of leaf 2H} and extend downwardly and radially thereof in the interior of leaf 218.130 open through the periphery of theseleaves. A fitting 244 is inserted in the outer opening of port 240 and is connected by means of the pneumatic line 246' with the right turn motor 3%. Also, a fitting 2 58 inserted in the outer openingof port 242 and is connected through the pneumatic line 250 with the lef turning motor 30a;

Referring now to Fig 3' only, four ports 252, 254, and 858 open through the bottom face of the fixed leaf 2:56 and also into the ports 2I6, fill, 228, and 23-2- respectively. The ports 252, 254, 256, and 258 are positioned in thebottom of; leaf 2 i it to overlie the through ports :92, 94, I96, and ass, respectively, in leaf L90 which is Positioned below leaf 2 i0 throughoutjthe entire range of travel of leaf I96. 'Al'so placed int'he lower face of the fixed leaf 230 are a pair of ports 260and 262 which: extend upwardly into the leaf to com- -"municate with the channels 264 and 266, respectively; inside leaf 210, which channels in turn respectivelycommunicate with the ports 220 and 222' in the leaf. 1 Port 260 overlies leaf I90 J'ust,.5

counterclockwise of port 200 in leaf I90 when leaf I lgflisneutrally positioned, while port 262 is pofs itioned to lie just clockwise of port 200 when leaf I90 is -neutrally positioned. Finally, a shoulder 268 'ncircles the central opening 2'l0- in leaf 2l0, .10 this shoulder resting upon the upper end of the central'stem 88. v

The stall leaf 280 of Fig 3 overlies thefixed leaf 210 and includes a pivothole 282 through 'whi ch fits the pivot 284 seen in Fig. 6 which passes through leaf 280 and is inserted in the hole 285 in'the top of fixed leaf 2 l 0, as seen inFig. 3. Leaf 280 also includes a central opening 286 .which "normallyoverlie's the central opening 210 in the 'fixedleaf 2l0 and is thereforesupplied with vacfrom the central stem 88. Placed around the central opening .266 are the four ports 288, 200,

292l'and 294 which respectively overlie the upper ep ninjes of ports 2m, 2m, 2211, and 222 in the upperg faceofleafjmwhen the stall leaf 280 is 'inifits normal or counterclockwise position. The upper innermost edge of each of the ports 288,

290,192; and'294 is notched at 288a, 290a, 292a, and 294a, respectively. A..pair of slots 296. and

Z290"extendfcompletely throughthe leaf 280 and are located as shown, and theoutside edge of each of; these slots is notched at', 296aand 298a in the same'fashion as, the four through ports in the z'a nha's thehole302 in which fits the pivot 303 whichconnects the forward-end of link 300 to leaf 280,, as seen in Fig... 6 to which reference is -.m ade. The rear end of link 300 is connectedlto ithe solenoid 460. which is supplied by power through conductors. 462 switch 464 beingin series with thefinterior. coil (not shown) of this solenoid.

{The cam. 460 is; mounted upon the shaft 466 which flis positioned bythe air speed unit 410 shown inbox form according to the instant as- .su'med airspeed of. the trainer, and cam. 466 has .aperipheral pattern and is arranged. so that .when theassumed .air speed of the traineris above the assumed stallingqspeed, switch 464 is closed. solenoid tiiillisenergized, and link 300 is in ,its normal or counterclockwise position, as showniriFig. 6, so that the stall leaf 280 is in its counterclockwise position above leaf 2l0,link 300 Ibeing so positioned against the tension of spring 0 t4l2 whichhas'one end attach'ed to link 300 and .th'e other to fixed member 414." When solenoid 460 is so energized, link 300 moves to theirear stop title engages the second machined. surface .fls-gnleaf 210 in Fig. 8.; Asseen in Fig. 3, placed in the lower a surface of leaf 1 260 is. the L-shaped .1'0 counterbore 308 which does not overlie any of the ports in the upper faceofleaf 2l0 when'the stall leaf 280 is inits normal or-counterclockwise position, but which when the stall leaf- 280 is in its clockwise position is positioned so that the end 3081) of thecounterbore overlies the port 220 in the upper surface of the-fixed leaf 210 while the end 308a thereof overlies the port 22 2 in the upper face of leaf 210' and the corner 3080 thereof overlies the vacuum'filled 'central opening 210 of leaf 210. Ports H6 and 2l8'inrle'af 2l0 are at the same time vented to the atmosphere by the rotation of'the stall leaf which uncovers the'ports. 'f)

t In Fig. 3 it will be seen that thecap 3l0 rests upon the upper surface of the stall leaf 280 and includes a fiat surface 3|2 out of which is cut a diamond-shaped counterbore 3H1 having slightly rounded corners. The raised lip 3H5 encircles the flat surface 3I2 which engages the upper surface of stall leaf 280, and integral with the upper portion of the cap 3L0 are the fingers '3l8 which engage the ball 320 attached to the lower end of the control stick 40, as seen in'FigLG to which reference is-"made. The control'sti'ck 40 passes through slot 480 in shaft 482 whichfis rotatably held in brackets 404 (only one shown in Fig. 6) integral with" base plate Blaf I A pin 486 pivots thestick 40 relative to shaft 482 to allow transverse 'move nent of the stick; A pair "of springs 48l are provided as seeriin 3, 'each .and-aft direction when stick 40 is released.

When the control stick 40 is inits neutral position and the fuselage I0 is in the level longitudinal and transverse position, and the stall leaf 2B0 in its normalor counterclockwise position, the vacuum cap 3| 0 will be positioned relative to the stall leaf 280 so that the fiat surface 3l2 thereof completely covers the ports 288,290, 292, 294,

296, 296a, 298'and 298a, the outer edges of the fiat surface 3l2 being displaced from the outer edges of these ports by a, few thousandths of an inch. The four sides of the diamond-shaped cut out portion 3| 4 overlap the. notches 286a,, 290a, 292a, and 294a to supply a limited but equal amount of vacuum to the four ports in the upper surface of leaf 2l0 which are connected tothe four main bellows, in order to provide stability to the fuselage l0.

Reference is now made to Fig. 6 where the simulated throttle control lever is designated by 500 and is rotatably mounted upon the transversely extending shaft 502 which may be suitably anixedwithin the fuselage l0. The position of lever-500 is also indicated in Fig. l. Pivotally attached to the bottom of the lever 500 by means of pivot 504 is the upper end of link 506 to the lower end of which is attached the arm 508 integral with valve leaf 5H] of the trim valve designated generally by 5|, the lower end of link. 506 being attached to arm 508 by pivot 5. The outsidefixed leaf of-valve 5| is numbered 5I2 and the inner movable leaf is numbered 5l 4,'a1l three-of the leaves of this valve being mounted estates '11 upon the horizontal trod 5E6 carried by the brackets 518 and 520.

Itwill be appreciated that when the simulated throttle control lever 506 is moved. ahead to simulate the opening of the throttle of a real plane, the .middle leaf 5H! ofvalve51 is rotated clockwise as seen in Fig. '6, and that when lever i500 i'ismov'ed in the opposite direction to simulate the closing of the throttle of a real plane the leaf :510 is rotated counterclockwise.

The position of leaf 5'I0 i-isat all times dependent upon the position of the simulated throttle control lever 560, and the position of this lever may be taken as a measure of the instant assumed power available.

Still referring to Fig. 6, it will be seen that there is formedintegrally with the upper endof the vertical spindle- I6 the upwardly extending projection [Ga against the rear edge of "which bears one end of the crank 522' which is rotatahlymdunted in the brackets 524 aflixed to the bottom 10a of the fuselage, aspring 525 having "one :end. affixed to crank 522 and its other end to the fixed member 528 in order to hold the crank-522 against the rear'edge of projection 6a stall times. Aifixed upon the other end of crank 522 is the arm 530 to the upper end of which is pivoted the rear end of link 532 by means of pivot 534-. The upper'endof link 532 is attached by pivot- 536 to theupper arm 538 of the bellcrank designatedgenerally by 539. The second arm of this 'bellcrank is numbered 540 and is carried. by the pivot 542 which in turn. is-carried by thesimulated elevator trim. lever 544 which in turn. .is rotatably mounted upon the previously described fixed rod 502. :A slot 1544a. placed in llever 5'44 and a suitable friction washer 5441)- is held againstlever 544 by screw 544e, which passes through slot 544a and is held by a suitable fixed part inside the fuselage, to prevent movements o'f'l'ev'er 544 except'by theapplication of manual force. The upper end of link 546 is pivoted to bell'crank 539 by pivot 548,. and. the lower end of "link 546 is pivoted to the arm 550' integral with leaf 514- of valve 5! by means of pivot 552.

Inasmuch as the axis of the lower portion of crank 522' is coincident with the transverse axis 401a, when the nose of fuselage I is lowered by an operation of the main control bellows 20, 22, 2'4 and 26, the coacti'on of. crank 522 with the projection l6a of the vertical spindle is maintains the arm 530 in a vertical position at all ti-mes. Pivot'5-34 carried by the upper end of arm 559 does not move, but the pivot 542 will rotate clockwise about the transverse axis 491a and away from the pivot 534. The movement of pivot 542' away from pivot "534 causes link 532 to rotate 'belicran'k 539 counterclockwise, and link '46 will move upwardly rotating the leaf 5M counterclockwise. On the other hand, when the nose of fuselage Ill is-raised the pivot 542 moves counterclockwise and closer to pivot 534, bellerank 539' is rotated clockwise and the leaf 514 is rotated inthe clockwise direction. 7

When the trim control 544 ismoved ahead to simulate the trimming of the elevators of the plane represented by the trainer to produce a other hand, when the simulated elevator trim control iever544 is moved to the rear to simulate the trimming "or the elevators of the plane represented by the trainerto produce a more nose- 12 up attitude, the pivot 5'42 carried. by leaf 544 will be rotated counterclockwise and link 546 moves upwardly rotating leaf 5M counterclockwise.

Consequently, leaf SM is at all times rotatably positioned about the axis of rod 516 in accordance with the combined position of fuselage l0 about the transverse axis 501w and the position of the simulated control lever 544. Driving of fuselage l0 and rearward movements of lever 544 produce counterclockwise motions of leaf 5|4, while raising the nose of fuselage -l 0 and forward movements of lever 544 result in clockwise motions of leaf 514.

Reference is now made to Fig. 9 which is a. detailed plan view of the leaves 510,. 5|2 and 5|4 of the trim valve 5l.,. and to .Figs. 4 and 10 which show the connections from the trim valve to the four main bellows andmain valve 50. It will be seen that the leaf 512 has four ports 560', 562,

center 566 for the reception of the rod 516, and

this leaf has four kidney-shaped ports 588., 590, 592 and 594 which pass completely through the leaf and are arranged to overlie the ports 560, 562, 564 and 566 respectively in leaf 5l2 throughout the entire range of travel ofle'af 5H1. The arm 506 integral with leaf. 519 has a hole .5! la therein for the reception. of the pivot 5' shown in Fig. 6.

'The'le'af '5l'4 is drilled "in the center at 596 for the reception of therod'. 5l6 shown in Fig. 11, and placed in the inner surface of this leaf are the two channels 598 and 000 which open into the center 596 and extend radially of the leaf to near the periphery thereof. The center lines of these two channels are I" apart and channel 598 is arranged to lie intermediate the two ports 592 and 594 in'l'eaf 511! when the leaves 'are neutraily positioned with respect to one another to provide a slight vacuum leak into ports 592 and 594. Similarly, channel 6'00is arranged'tolie between the ports 58 8 and 560 in leaf 5"] when the leaves are neutrally positioned with respect to one another to provide a slight vacuum leak into ports 588 and 590. The four atmosphere ports 602, 604, 606 and 668 pass completely through leaf 5|4, port 602 being arranged to lie slightly clockwise of port 538, port 604 being arranged to lie slightly counterclockwise of port 590', port 606 being arranged to lie slightly counterclockwise of port 592 and port 608 being arranged to lie slightly clockwise of port 594 when leaves 5 I 0 and 5! are neutrally positioned with respect to one another.

Reference is now'made to'Fig. 11 where it will be seen that the fixed leaf "512 is afii'xed upon the 'fixed'rod 5I6 by means 'ofset'screw H0, and that leaves 510 and 514' are freely mounted upon the rod 5l6. The outer end of rod 5"? is drilled at Hi2 and the coupling 6| 4 is inserted in the outer end of the drilled portion and is connected through the pneumatic line 82 to the coupling 80 shown in Fig. '4 and inserted in port 14 in the bottom leaf 52 of the main valve. The diameter of rod 5L6 is turned down at 616 and a plurality of radially extending ports 610 connect the center The two channels 598 and Operation Turning action.- Assuming that the rudder pedals 42 and 44 are in their neutral positions,

that the stick 40 is in its neutral position, and

"that thefuselage I isin the level transverse or non-cranking position, the various leaves of the main valve 50 will all be in their neutral rotational positions, and thefuselage I0 will be in a stationary position. Assuming that the left rudder pedal 42 is pressed ahead, through the previously describedmechanism interconnecting the rudder pedals and the rudder leaf I of valve 50, the leaf I20 will be rotated counterclockwise as seen in Fig. 2 through an angle proportional to the magnitude of displacement of the left rudder pedal 42 from its neutral position. jThe' figure-of-eight counterbore I34 in the bottom of leaf I20 will be moved into a position overlapping the port I08 by an amount dependent j upon the displacement of leaf I20 from its neu- "t'ral position. The limited supply of vacuum fed intothe figure-of-eight counterbore I34 through the restricted port I32 in leaf I20 will pass through the port I08 in leaf I00 into port 54 in leaf 52 and by means of fitting 58 and pneu matic line 60 of Fig. 4 will be introduced into the left turning motor a, Simultaneously, the atmosphere slot I52 in the bottom of leaf I20 will be moved into a greater overlapping position with respect to the port H0 in leaf I00, the

amount of the overlap being dependent upon the magnitude of forward displacement of the left rudder pedal 42. Qpass through the port H0 and through port 55 in the bottom leaf 52 and will be carried by the Atmosphere will accordingly fitting 64 and pneumatic line 66 to the right turning motor 30b. The admission of vacuum to the left turning motor and of atmosphere to the right turning motor will energize the turnthe motors to rotate the output wheel 34 which by means ofbelt 36 and spindle 38 will produce a rotation of the fuselage It to the left. The rate of rotation will be dependent upon the magnitude of displacement of the left rudder pedal 42 from its neutral position, and in any event will be relatively slow because of the limited amount On the other hand, assuming the same general circumstances except that the right rudder [pedal 44 is moved. ahead instead of the left rudder pedal 42, the rudderleaf I2llwill be rotated clockwise from its neutral position and the limited supply of vacuum in the figure-of-eight counterbore I34 will pass through the port IIO because the figureof-eight counterbore I34 will overlie port IIO by an amount dependent upon the displacement of the right rudder pedal 44.

[Communication will be made with the right turning motor 30h through the port 56 in leaf 52 and through the fitting 64 and pneumatic line 66. Simultaneously, the atmosphere slot I48 in the bottom of leaf I20 will be rotated into a position overlyingthe port I08 in leaf I00 toa greater extent, the amount of increased overlap also being dependent upon the forward displacement of the right rudder pedal 44. Atmosphere will be carried to the left turning motor 30a through the port 54 in leaf 52 and through fitting 58 and pneumatic line 60. The admission of vacuum to the right turning motor 301) and of atmosphere to the left turning motor 30a will result in an energization of the turningmotors in the opposite direction from that previously 10' described to produce a turning of the fuselage I0 to the right. The rate of turn will be dependent upon the magnitude of displacement of the right rudder pedal 44, and, for the same reason as previously explained, will be relatively slow because of the limited amount of vacuum available in the figure-of-eight counterbore I34.

Turn with Dania-Assuming that the manually operated controls and fuselage I0 as well as the leaves of valve 50 are all neutralized, and that the fuselage I0 is then banked to the left, as will be later more fully described, the leaf I00 of valve 50 will be rotated clockwise through an angle proportional to the degree of bank. The port 2 will be brought into an overlapping position with respect to the vacuum port 98 in the upper surface of the leaf 52, admitting an increased supply of vacuum into the counterbore I34 in the bottom of leaf I20. At the sametime, the port I08 will be brought into an underlappi'ng position with respect to counterbore I34 and the increased supply of vacuum in counterbore I 34 will pass through port I 08, port 54 in leaf 52,

I fitting 53 and pneumatic line 60 to the left turning motor 30a. Simultaneously, the port III! in leaf I 00 will be brought into an increased underlapping position with respect to the atmosphere slot' I52 in the bottom of leaf I20, and an in- 30a and of increased atmosphere to the right turning motor 30b will result in an energization of theturning motors to cause the fuselage I0 to rotate to the left. In view of the fact that the supply of vacuum in the port 98 of leaf 52 is of greater exhausting capacitythan the supply of vacuum in port I34 which is admitted thereto through the restricted port I32, it will be appreciated that the rate of rotation of the fuselage I0 to the left in response to a banking to the left of the fuselage may beconsiderably greater than the rate of rotation of the fuselage to the left produced only by a forward movement of the left rudder pedal 42.

On the other hand, assuming the same circumstances with the exception that the fuselage I 0 is banked'to the right instead of to the left, the leaf IEO will be rotated counterclockwise of its neutral position and port H4 in that leaf will be moved into an overlapping position with respect -"creased supply of vacuum admitted into the counterbore I34 in the rudder leaf will be communicated through ports IIO+and I55, fitting 64 direction.

15 and pneumaticline '66 to the right turning motor 30b. Simultaneously, the port I88 will be moved into an increased underlapping position with respect to the atmosphere slot I48 in the bottom of leaf I20, and increased atmosphere will be passed through the port I08, port 54, fitting 58 and pneumatic line 80 t the left turning motor 304:. The admission of vacuum to the right turning motor 30b and of increased atmosphere to the left turning motor 30a will result in an energization of the turning motor to rotate the fuselage I0'to the-right. It will be appreciated that the rate of turning to the right will depend upon the magnitude of displacement of the leaf I00 .from its neutral position, which in turn depends upon the degree of bank of fuselage I0 to the right, and that the rate of rotation may be considerably greater than the rotation achieved by the pressing forward of the right rudder pedal alone because the supply of vacuum to the port 98 in the top of leaf 52 is, as previously explained, of greator exhausting capacity than that fed into counterbore I34 through port I32.

It will be noted that the rudder leaf I20 is rotated counterclockwise in response to a forward movement of the left rudder pedal 42 to produce a turning to the left of fuselage It, while leaf I00 is rotated clockwise in response to a banking to the left of fuselage I0. At the same time, leaf I20- is rotated clockwise in response to a forward movement of the right rudder pedal 4d, while leaf I00 is rotated counterclockwise inresponse to a banking to the right of the fuselage. Rotation of the rudder leaf I20 in one direction bringsthe ports and channels in the bottom of that leaf into z the same position with respect to the ports in leaf I00 as does arotat-ion of leaf I00 in the opposite Consequently, when the left rudder pedal @2- is moved ahead to rotate leaf I28 counterclockwise to produce a relatively slow turning to the left of fuselage I0, and then the fuselage is banked to the left at the same time, as should be done to simulate the" correct handling of a plane in actual flight when a turn to the left is being made, the banking action of the fuselage rotates leaf I00 clockwise to produce a much more rapid rotation of the fuselage It! to the left than could be accomplished by rudder pedal action only. When the right rudder pedal 44 is pressed ahead to rotate leaf I20 clockwise to slowly turn the trainer to the right, and then the fuselage is banked to the right, as should be the case, a counterclockwise rotation of leaf I00 occurs, and the rotation of the fuselage I0 to the right is greatly increased-simulating the corresponding responses of a plane in actual flight under corresponding actual circumstances.

It will be noted that the turning of th fuselage It in one direction as a result of a displacement of one of the rudder pedals may be lessened, offset, or even reversed by banking the fuselage I0 in the opposite direction by varying amounts.

Effect of bank on trim.--It will be noted that as the fuselage I0 is banked to the left or right, the port ltd is moved out of overlapping position with respect to the port I0 in the leaf 52 and the port I06 is moved out of overlapping position with respect to the port It in leaf 52 by an amount dependent upon the degree of bank of fuselage I0. Accordingly, the amount of vacuum fed from the slot I35 in the bottom of leaf I20 through port I04 to port I0 and then through channel I2, port I4, fitting 80 and pneumatic line 82 to-the trim valve 5i, shown in Fig. 4, will be decreased and the vacuum in channel I40 in the bottom of leaf I20 fed through port I06 in leaf Iiiil and port 16 in leaf 52 and throughchannel I8, port 74, fitting and pneumatic line -82-to the valve 5| will also be decreased. Consequently, the supply of Vacuum to the trim valve 5| is progressively reduced as the fuselage I0 is banked either to the left or right, and when fuselage I0 :is banked to the extreme left-or right all vacuum to the trim valve '5I is cut off.

Bank with turn.Assuming the fuselage It to be in a simulated straight and level flight with the manually operable controls therein neutralized, and the leaves of the main control valve 59 also neutralized, and assuming that the rudder leaf I28 is rotated counterclockwise in response to a forward movement of the left rudder pedal 42 to produce a turning of the fuselage it to the left, the vacuum port It; in the upper surface of the rudder leaf I20 will be moved into underlappin-g position with respect to the port I" in the fixed leaf I60 and vacuum will pass through port I'M, through the port I92 in leaf I90, and through port I52 into port 2I6 in leaf 2"). From port 2IB vacuum will be admitted to the left rear bellows 24 by means, of fitting 224 and pneumatic line 226'. Simultaneously, the left or counterclockwise end of the vacuum slot I30 in the upper surface of leaf I20 will move into underlapping relation with the port I32 in leaf I60, and vacuum will pass through port I82, port 596 in leaf I90, port 256 in the bottom of leaf 2m, port-220 in leaf 2H and by means of fitting 232 and pneumatic line 234 will .pass to the left front bellows 2-0; Simultaneously, the atmosphere slot I58 in the upper surface of leaf I20 will be moved into underlapping position with respect to port I16 in leaf I60, and atmosphere will pass through port I16; port I94in lea-f I00, and port 254 in the bottom of leaf 2 I0 into. the port M8 in the same leaf, and then by means-of fitting 220, and pneumatic line 230 to the right rear bellows 2-6. Also simultaneously, the atmosphere port I54: in the upper surface of the rudder leaf I20 will move into underlapping position with respect to the port I84 in leaf I60, and atmosphere will pass through port I84, port I98 in leaf I and port 258 in leaf 210 into the port 222 in leaf M0, andthen by means of fitting- 236 and pneumatic line 238 to the right front bellows 22. Consequently, a turning-of the fuselage I0 to the left results in an admission of vacuum into the left rear bellows 24 and left front bellows 20, and of atmosphere into the right rear bellows 26 and right front bellows 22. The two left bellows will be contracted and the two right bellows expanded, and a banking of the fuselage I 0 to the left results. It will be appreciated that the degree of resultant bank will depend upon the volume of vacuum and atmosphere admitted into the bellows, which in turn will depend upon the magnitude of displacement of the leaf I20 from its neutral position. Accordingly, the degree of automatic banking of the fuselage to the left in response to a turning of the fuselage to the left will be proportional to the rateof turning of the fuselage attributable to the displacement of the rudder pedal from it's neutral position.

Assuming that the rudder leaf I20 is rotated clockwise of its neutral position by a forward displacement of the right rudder pedal 44, the right end of the vacuum slot I30 in the upper surface of leaf I20 will be moved into underlapping position with respect to the port I84, and by means of the same described path interconnectin'g port I84 andthe right front bellows 22, vacuum willbe admitted'ihtobellom 22; the vacuum port I46 in the uppersurface of leaf I20 will be moved into underlapping position with respect to port I16 in leaf I60,and vacuum will pass from port I76 to the right rear bellows 26 through the previously describedjpath; the at- 'mosphere slot I56 in theupper surface of leaf I20 will be moved into underlapping position with respect to port I74 inleaf I60, and atmosphere will pass from port I14 through the previously described path to the left rear bellows 24; and the atmosphere port I50 in the upper surface'of leaf I20 will be moved into underlappingposition with respect to port I82 in leaf I60, and atmosphere will pass from port I82 through the previously described path to the left front bellows 20. Consequently, vacuum will be admitted to the two right bellows 22 and 26 while atmosphere will be admitted to the left bellows 20 and 24, producing a banking of the fuselage I to the right. The degree of bank will depend upon the volume of atmosphere and vacuum'admitted tothe fourbellows, which volume depends upon the magnitude of forward displacement'of the right rudder pedal 44.

Nose down with bank.When the fuselage I0 is banked to the left, the leaf I90 is rotated counterclockwise through an angle proportional to the degree of bank. The port 200 in leaf I90 is moved into overlapping position with respect to the port I86 in leaf I60 which in turn overlies the vacuum slot I30 in the upper surface of leaf I20, and at the same time port 200 in leaf I90 moves into underlapping position with respect to the port 260 in the under surface of leaf 2I0. Vacuum willbe passed from slot I30 through ports I86 and 200 into the port 260 in leaf 2I0 and thence through channel 264 in leaf 2I0 to port 220 and then through the previously described connection to the left front bellows 20. At the'same'time the port' I94 will be moved into overlapping position with respect to the atmosphere slot I80 in the upper surface of leaf I60, and atmosphere will pass through ports I94 and 254 into port 2 I8 in leaf 2 I0, and thence through the previously described path to the right rear bellows 26. Consequently, a banking of the fuselage-I0 to the left results in an admission of vacuum to the left front bellows 20 and of atmosphere to the right rear bellows 26, to produce an increased lowering of the front left corner of the fuselage and an increased raising of the right rear corner thereof, to simulate the automatic nosing down of a plane in actual flight as a result of a banking to the left thereof. As

previously explained, the automatic banking. to

the left also produces an automatic turning to the left.

, Onthe other hand, when the fuselage I0 is banked to the'rightthe leaf I90 is rotated clockwise fromits neutral position, and port 200 in leaf I90 is moved into overlapping position with respect to the port I88 in leaf I60,,which last mentioned port overlies the vacuum slot I30 in the upper face of leaf I20. Consequently, vacuum is passed through port 200 to the port 262 in the lower face of the fixedleaf 2I0, and thence into channel 266 and port222 in leaf 2I0, and then along the previously described path to the right front bellows 22. Simultaneously, the port I92 infleaf I 90 is moved into'overlapping position with respect to thefatmosphere slot II8'in' leaf I60, and atmosphere passedthroughport I 92 and, port 252 in leaf 2'I0into' port 2I6 inleaf 2I0.

From. port 2I6,atmosphere passes along the previously described pathto the left rear bellows 24. Consequently, a banking, of the fuselage to the right results in 'an admission of vacuum to the right front bellows 22 andof atmosphere to the left rear bellows 24, resulting in a further lowering of the right front corner of the fuselage and in a further raising of the left rear corner, thus simulating theautomatic dropping of the nose of a, plane bankedto the right.

It will be appreciated that the magnitude of the nosing down of the fuselage I0 in response to the banking to the left or right thereof will be proportional to the degree of bank.

Pitching and banking of the fuselage in response to control stick movement-Assuming that the student in the trainer moves the control stick 40 directly ahead, the stick will rotate the shaft 482 held by bracket 484, as seen in Fig. 6, and the lower end of the control stick and ball 320' will move to the rear. The rearward movement of this ball engages the fingers 3I8 integral with cap 3I0 and the cap is moved to the rear. The diamond-shaped cut out portion 3I4 seen in Fig. 3 will then be brought into overlapping position with respect to the ports 292 and 294 and increased vacuum will be applied from the central opening 266 in leaf 280 through the ports 292 and 294 and ports 220 and 222 in leaf 2I0 as well as through the previously described interconnecting elements to the two front pitching bellows 20 and 22. Simultaneously, the rearward movement of plate 2I2 will uncover the to the atmosphere, and atmosphere will be passed through the ports 2I6 and 2I8 in leaf 2I0 to the left rear bellows 24 and right rear bellows 26. The admission of increased vacuum into the two a front bellows and of atmosphere into the two rear bellows will result in a collapsing of the first pair of bellows and in an expansion of the second pair of bellows, and the nose of fuselage I0 will be lowered, thus simulating the lowering of the nose of a plane in actual flight in response to a forward movement of the control stick.

, On the other hand, assuming that the student in the trainer moves thecontrol stick 40 to the rear of its neutral position, the cap 3I0 will be moved ahead of its neutral position and increased vacuum will be applied to the two ports 288 and 280 while the ports 292 and 294 will be vented to the atmosphere. Through the previously described connections, increased vacuum will be admitted to the rightrear bellows 26 and left rear bellows 24, while atmosphere will be admitted to theleft front bellows 20 and right front bellows 22. The first pair of bellows will be contracted and the second pair will be expanded, resulting in a raising of the nose of fuselage I0, thus simulating the raising of the nose of a plane in actual flight as a result of a movement to the rear of the control stick.

With the control stick in its neutral position and the'trainer fuselage I0 in the level longitudinal and transverse position, when the student in the trainer movesthe stick 40 to the left,

1 l9 banking or pane in actual flight to the left in response to a movement to the left of the control stick. It will be appreciated that a'movefment of the control stick 40 to the right will result in an application of increased vacuum to the right front bellows 22 and right rear bellows 26 and of atmosphere to the left front bellows 20 and left rear bellows 24, producing a banking of fuselage 10 to the right, simulating the banking ofa plane in actual flight to the right in response ,to a movement to the right of the control stick. Movements of the control stick 59 in any direction other than straight fore and aft or directly sidewise results in applying increased vacuum to or venting the four main ports in the stall leaf 285 toproduce the proper combination of expan- 'sion and "contraction of the four main bellows to give motions of the fuselage 10 about its transverse and longitudinal axes to simulate the motion of a real plane about its two corresponding axes in response to corresponding movements of the stick in the plane.

' 'Aileron drag efiect.When the control stick 49 is moved to the left of its neutral position, the vacuum cap 310 moves to the right, first venting the notch 298a to the atmosphere and then venting the port 293 to atmosphere, and permitting atmosphere to pass through port 298 in leaf 289 and port 242 in leaf 219 and by means of fitting 248 and pneumatic line 250 to the left turning motor 39a. At the same time, the cut-out portion S lt-in cap 319 is moved into overlapping position with'respect to port 295 in leaf 289, and vacuum is applied through port 296 in leaf 236 and through port 245 in leaf 219, as well as through fitting 244 and pneumatic line 245 to the right turning motor 85b. The admission of atmosphere to the left turning motor 391) and of vacuum to the right turning motor produces a slight turning to the right of fuselage 16, thus simulating the aileron drag effect of a plane in actual flight which causes the plane to first turn slightly to the right in response to a left movement of the stick control. However, as the actual banking of fuselage 19 to the left commences, as previouslyexplained the leaf 105 will be rotated clockwise to admit vacuum to the left bellows 29 and 24, and a larger volume of vacuum to the left turning motor 39a and of atmosphere to the right turning motor 391), and a turning to the left of the fuselage will be produced.

7 On the other hand, when the control stick 46 is moved to the right the resulting movement to the left of the vacuum cap 310 results in a venting of the notch 296a and port 296 to the atmosphere, and in an application of vacuum to the port 298. Atmosphere is applied to the right turning motor 39b and vacuum to the left turning motor 313a, and the fuselage initially turns to the left, simulating the initial turning to the left of a plane in actual flight in response to a movement to the right of the control stick. However, as the bank to the right commences, as previously explained, the automatic turn with bank effect will overcome the initial adverse turning effect, and the turn of fuselage 16 will be reversed and to the right.

' Stall efiect.-When the stall leaf 280 is rotated into its clockwise position as previously explained in the presence of an air speed at or below the assumed stalling air speed, the stop 3B6 engages the machined surface 418 on valve section 216 seen in Fig. 8, and the end 3980. of the counterbore 398 in the bottom of leaf 2 89 will overlie the port 222 in the upper face of leaf 210, and the end 5081) ofcounterbore 308 will overlie the port 226 in theuppe'r face of leaf 210. The outer corner 3880 of counterbore 3-08 will overlie the central vacuum-filled port2'11l'in leaf 210, and consequently vacuum, will be applied to' the ports 220 and 222 and thence to the left front bellows 28 and right front bellows 22. At the same time, the clockwise rotation of the stall leaf 286 will uncover the ports 216 and 218 and these ports as well as the left rear bellows 24 and right rear bellows 25 which are connected thereto will be vented to the atmosphere. The resultant contraction of the two front bellows and expansion of the two rear bellows will produce a rapid nosing down of the fuselage 10, thus simulating the stalling of a plane in actual flight.

Trim action..Assuming that the fuselage 16 is in straight and level flight, the leaves 519 and 514 of valve 51 will beneutrally positioned with respect to oneanother and a slight vacuum leak will pass equally from the channels 598 and 6119 in leaf 514 of valve 51 through the ports 588, 590, 592 and 594 in leaf 519 and through the ports 5611, 552,, 564 and 566 in leaf 512 and along the four pneumatic lines connecting leaf 512 with the four main bellows. Assuming that the student in the trainer then presses the control stick 40 ahead to lower the nose of the fuselage, and then the control stick 4!] is released, through the previously described control stick spring centering means 585a. of Fig. 6, the control stick 46 will be returned to its neutral position so that the valve cap 310 is centered with respect to the ports in the stall leaf 280. The lowering of the nose of the fuselage will produce an upward movement of the link 546. which connects with the leaf 514 of valve 51, and leaf 514 will be rotated counterclockwise of its neutral position. The vacuum channel 598 will then overlie the port 592 in leaf 510 and vacuum' channel 600 will overlie the port 599. Vacuum will be applied from ports 599 and 592 through ports 564 and 562 to the two rear bellows. Simultaneously, the atmosphere port 602 will be moved into an overlying position with respect to port 588 and the atmosphere port 695 will be moved into an overlying position with respect to port 594-. Atmosphere will pass through ports 588 and 594 in leaf 519 and thence through ports 5.60 and 566 to the two front bellows. The admission of vacuum to the rear bellows and atmosphere to the front bellows will result in a gradual raising of the nose of fuselage 19, and this raising will continue until the fuselage hasbeen returned to its previous flight position, at which time the leaf 514 will again be centered with respect to leaf 5 11), and the raising of the nose. of the fuselage will stop.

On the, other hand, assuming that the student in the trainer pulls the control stick 41! to the rear of its neutral position to place the fuselage in a climbing attitude, and then releases the control stick, the previously described'control stick centering means will return the stick to its neutral position and will return the cap 316 to its neutral position with respect tothe ports in the stall leaf 280. The raising of the nose of the fuselage will result in a clockwise rotationof the leaf 514 from its neutral position, and vacuum will pass from the channels 598 and 690 in leaf 514 through the ports 5.9.4 and 588 in'leaf 516 and thence through thepiorts 5.69 and 566 and the intermediate connecting pneumatic lines to. the two front bellows. Simultaneously, the atmosphere. ports 6M and606 inleaf514 will be placed intooverlapping position with respect to the ports5911 and 592 in leaf 5 10,v

at-143cm and atmospharelwill beadmitted throughthe ports 59B and 5,92-and ports 562 and 564in leaf 5|2, as well as through the intermediate connectingpneumatic lines to the two rear bellows.

.The admission of vacuum to the forward bellows Consequently, the provision of the trim valve of this invention provides means whereby a forward-or rearward movement of the control stick to change the pitch attitude of the fuselage and a subsequent releasing of the control stick results in a gradual returning of the fuselage l to its previous night attitude, thus simulating the corresponding characteristic of a real plane in actual flight Assuming that the fuselage U is in a simulated trimmed flight position, and the throttle lever 500 is moved ahead to simulate the opening of the throttle of areal plane, the link 506 moves downwardly and leaf 0 is rotated clockwise of its neutral position. Theclockwise rotation of leaf 5H! will result in an application of increased vacuum to the ports 590 and 592 from the channels 598 and 600. in leaf 5M, and this increased vacuum will be applied to the two rear bellows through the previously described connections. Simultaneously, atmosphere will be applied to the ports 588 and 594 in leaf 5|0 through the ports 602 and 698 in leaf.5 |4, and atmosphere will be applied through the previously described paths to the two front bellows. The application of vacuum to the two rear bellows and of atmosphere response to th e raising of the nose of the fuselage throughthe sameangle as leaf 5|!) was rotated in response to the forward movement of the simulated throttle lever 500. At that time, the two leaves 5|!) and 5|4 will be centered with respect to one another, and the raising of the nose of the fuselage will stop.

, On the other hand, when the student in the trainer moves the simulated throttle control lever 50!! to the rear to simulate the, closingof the throttle in the plane represented by the trainer, the link 566 is moved upwardly rotating thecenter leaf 5|li cfvalve 5|"counterclockwise. An application of increased vacuum to the front bellows and of atmosphere-to the, rear bellows will result, and the nose of the fuselage l0 will gradually be lowered. The loweringof thenose of the fuselage will result in an upward movement of link 546 and in a counterclockwise rotation of leaf 5|4, and the raising of the nose of the fuselage will continue until leaf '5|4 has beenrotated counterclockwise through the same angle in response to the raising of the nose of the fuselage as the center leaf 5|0 was rotated in response to the retarding of the simulated throttle lever 500. At that time the two leaves 5H) and 5|4 will be centered with respect to one another, and the,

fuselage motion will cease.

Consequently, this invention also includes means whereby the pitch attitude of the fuselage is responsive to the setting of the "simulated throttle control lever, thereby simulating the characteristic of a real plane wherein the attitude of the plane is responsive to the setting of the throttle control lever.

When the simulated elevator trim control lever 544 is moved ahead, to simulate the setting of the elevator trim control lever in areal plane to produce a more nose-down flight attitude, the pivot 542 of bellcrank 530 is moved downwardly resulting in a downward movement of link 546 and in a clockwise rotation of the movable leaf 5| 4 'of the trim valve 5|. The clockwise rotation of leaf 5|4 will result in an application of increased vacuum to the two front bellows and of atmosphere to the two rear bellows, and the nose of the trainer .will gradually move downwardly. As the nose of the trainer moves downwardly the link 5252 will rotate the bellcrank 539 counterclockwise about the pivot 540 until the leaf 5|4 has been returned to its previous position, at which time the nosing down of fuselage |0 will cease. The nose of fuselage in will then be lower and remain lower than the previous position thereof by an amount dependent upon the forward movement of simulated trim lever 544.

On the other hand, when the simulated trim control lever 544 is moved to the rear of a given position, the link 546 is moved upwardly and rotates the leaf 5|4 of valve 5| counterclockwise resultingin an application of vacuum to the two rear bellows and of atmosphere to the two forward bellows; The nose of the fuselage gradually is raised, and raising of the nose of the fuselage will result in a clockwise rotation of the leaf 5|4, and the gradual raisingof the nose" of the fuselage will continueuntil leaf 5|4 has been returned to its previous position. The nose of the fuselage will behig'her and will remain higher than its previ-- ous flight attitude by an amount dependent upon the movement of the trim lever 544.

-The provision of the simulated elevator trimming control 544 and the apparatus associated therewith provides means whereby the operational effects of the elevator trimming controlof areal plane may be simulated. I

It has been previously explained that the supply of vacuum to the trim valve 5| is dependent upon the bank attitude of the fuselage I0, and that as the banking of the fuselage is increased the supply of vacuum to this valve is gradually decreased and whenthe fuselage I0 is in its extreme'banking position no vacuum is admitted to the trim valve 5|. Consequently, the previously described movements of the fuselage controlled by the trim valve5l are gradually eliminated by a banking 0f the fuselage. The gradual elimination of the effects of the trim valve 5| b'y a'banking of. the fuselage simulates the flight characteristics of a real plane wherein the inherent stability of a plane about its transverseaxis gradually decreases with a banking of the plane,'and wherein the pitch attitude of the planebecomesless responsive to the position of the throttle control lever as the plane is banked, and wherein the elevator trimming means of the plane gradually lcsetheir effect as the plane is' It will be appreciated that many changes may be made from the disclosed embodiment of this invention, without departing from the substance thereof as set forth in the following claims.

We claim:

1. In a grounded aviation trainer of th type comprising a fuselage universally mounted with respect to a stationary base and four expansiblecontractible bellows connected to the fuselage for pivoting the same upon the universal joint, a first valve section comprising a flat surface, a central opening and four additional ports in said flat surfacezsymmetrically spaced about said central opening, a pneumatic connection between each of said four ports and a diiferent one of said bellows and a source of reduced pressure connected to said central opening, a second valve section having a flat surface arranged to lie against the flat surface of said first valve section, five ports in said second valve section each arranged to respectively overlie a different one of the five openings in said first valve section when said second valve section occupies a first predetermined positionrelative to said first valve section, a channel in the flat surface of said second valve section arranged to connect the central opening of said first valve section with two of the other ports in the same section when said second valve section occupies a second predetermined position, said second valve section being shaped'and arranged to vent the other two ports in the first valve section to the atmosphere when the second valve section is in, the second predetermined position, a plate arranged to substantially cover the said four ports in said second valve section when the plate is neutrally positioned, a chamber formed in said plate and arranged to overlie the central port in said second valve section, a manuallymovable member connected to said plate for moving said plate relative to the ports in said second valve section, where vacuum is selectively applied'to the ports in said second valve and the ports therein are selectively vented to the atmosphere when the second valve section is in the first mentioned predetermined position, and means for positioning said second valve section in either of said predetermined positions.

2. The structure set forth in claim 1 in which the means for positioning the second valve section comprises a. unit responsive to changes in the assumed air speed of the trainer, and the said unit. is connected to the valve section to position the same in the first predetermined position when assumed air speed is. above a predetermined amount and in the second predetermined position when assumed air speed is below the predetermined amount. 7

3. In a grounded aviation trainer of the type comprising a fuselage universally and rotatably mounted with respect to a stationary base and four expansible-oontractible bellows connected to said fuselage for pivoting the same upon the universal joint as well as a pair of turning motors for rotating the fuselage with respect to the stationary base, a valve section comprising a flat surface, six ports symmetrically arranged in said surface, a pneumatic connection between each of four of said ports and a different one of said bellows and a pneumatic. connection between each of said two other ports and a different one of said turning motors, a plate arranged to substantially cover all of said ports when the plate is neutrally positioned, a vacuum chamber formed in the center of said plate, av manually controllable member, and a connection betweensaid manually controllable member and a said plate arranged to move said plate in any direction radially of said flat surface dependent upon the direction of movement of said manually controllable member, whereupon said ports-are selectively opened into said vacuum chamber and vented to the atmosphere to cause said fuselage to turn slightly in the opposite direction ofa banking thereof.

' a. In a grounded aviation trainer of the type havinga fuselage universally mounted with respect to a stationary base and four expansiblecontractible bellows for causing the fuselage to pitch and bank to simulate the pitching and banking of a plane in actual flight, the combination of a valve therein connected to said bellows to control the same, a lever in said fuselage simulating the throttle control lever of a real plane, means interconnecting said lever and said valve for operating said valve according to the position of said lever, a connection to said valve responsive to the pitching position of said fuselage for operating said' valve according to the pitching position of said fuselage, and means respon'sive to the banking position of said fuselage for diminishing the control of said valve on the pitching position of said fuselage as the banking of said fuselage increases.

5. The structure set forth in claim 4 in Which the valve comprises two movable leaves the relative positions of which. partially control the said bellows, and the said simulated throttle control lever is connected to one of the leaves to move. the same to change the pitch attitude of the fuselage in response to a movement of the lever, and the said connection responsive to the pitching position of the fuselage. is connected to the other movable leaf and rotates the leaf as the pitch attitude of the fuselage changes in the same direction as the movement of the first heat until the second leaf has been moved through the same angle as the first leaf.

'6. The structure set forth in claim 5 in which a second lever simulating the elevator trim lever of areal plane is provided, the said lever being differentially. connected to. the second movable leaf withthe connection responsive to the pitchingpo'sition of the fuselage.

STANLEY I. HAYES.

THEODORE HERSKOVITS.

REFERENCES CETED The following references are of record in the file of this. patent:

UNITED STATES PATENTS Number Name Date 2,09%8 5'7 Link Nov. 23, 1937 2,358,016 Link Sept. 12, 1944. 

